Nuclear deoxyribonucleic acid content in inverted papilloma of the urothelium

We analyzed formalin-fixed and paraffin-embedded materials from urothelial inverted papillomas using flow-cytometric DNA analysis to investigate the intrinsic nature in terms of the malignant potentials. DNA indices of the inverted papillomas ranged between 1.00 and 1.26 with a mean value of 1.12. The percentage of S phase of a tumor DNA histogram showed greater values in every case compared with a normal DNA histogram. This tumor form could be thus regarded as a diploid neoplastic disease with a relatively higher proliferative activity, although 1 case showed an aneuploid pattern (DNA index = 1.26), in which bladder carcinoma developed subsequently.